US7734017B2 - Anti-scatter-grid for a radiation detector - Google Patents

Anti-scatter-grid for a radiation detector Download PDF

Info

Publication number
US7734017B2
US7734017B2 US11/573,358 US57335805A US7734017B2 US 7734017 B2 US7734017 B2 US 7734017B2 US 57335805 A US57335805 A US 57335805A US 7734017 B2 US7734017 B2 US 7734017B2
Authority
US
United States
Prior art keywords
radiation
scatter
grid
lamellae
electrodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US11/573,358
Other languages
English (en)
Other versions
US20090225938A1 (en
Inventor
Gunter Zeitler
Gereon Vogtmeier
Klaus Jurgen Engel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V. reassignment KONINKLIJKE PHILIPS ELECTRONICS N.V. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ENGEL, KLAUS JURGEN, VOGTMEIER, GEREON, ZEITLER, GUNTER
Publication of US20090225938A1 publication Critical patent/US20090225938A1/en
Application granted granted Critical
Publication of US7734017B2 publication Critical patent/US7734017B2/en
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
    • G01T1/164—Scintigraphy
    • G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
    • G01T1/1648—Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
    • G01T1/164—Scintigraphy
    • G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
    • G01T1/1644—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using an array of optically separate scintillation elements permitting direct location of scintillations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/29—Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
    • G01T1/2914—Measurement of spatial distribution of radiation
    • G01T1/2985—In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis)
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T7/00—Details of radiation-measuring instruments

Definitions

  • the invention relates to an Anti-Scatter-Grid for a radiation detector, to a radiation detector with such an Anti-Scatter-Grid, to an examination apparatus with such a detector, and to a method for the determination of scattered radiation impinging on a radiation detector.
  • an Anti-Scatter-Grid (ASG) in front of the detector, wherein said grid comprises radiation absorbing lamellae which define channels through which radiation from a target direction may freely pass, while scattered radiation coming from other directions will be largely absorbed. It is however impossible to remove all scattered radiation with an Anti-Scatter-Grid, and therefore the contribution of scattered radiation to a measured image signal remains a problem, particularly in image regions of weak signal intensity.
  • the U.S. Pat. No. 6,618,466 B1 proposes for example a method in which the contribution of scattered radiation to an image is determined via the generation of images with and without a beam stop array and the application of interpolation techniques. Such a laborious method is however hardly to integrate into the normal medical workflow.
  • This object is achieved by an Anti-Scatter-Grid, a radiation detector, an examination apparatus and a method.
  • the invention relates to an Anti-Scatter-Grid for a radiation detector which comprises lamellae that strongly absorb radiation of a certain spectrum which shall be observed by the detector, for example X-radiation.
  • the radiation may pass freely only through (void or transparent) channels which are established between the lamellae.
  • the channels thus define lines of sight along which radiation may reach a detector at the “backside” of the Anti-Scatter-Grid.
  • the Anti-Scatter-Grid may be one-dimensional, wherein the channels are planes between parallel lamellae, or two-dimensional, wherein two sets of parallel lamellae cross and define channels.
  • the channels/lamellae may for example be parallel to each other or focused on a certain point (typically a radiation source).
  • a certain point typically a radiation source.
  • it is an important feature of the radiation absorbing lamellae that they are adapted to produce a signal that indicates the amount of radiation absorbed by said lamellae.
  • the signal may for example be proportional to the total energy of the absorbed radiation.
  • An Anti-Scatter-Grid of the aforementioned kind absorbs scattered radiation coming from directions other than a target direction defined by the channels of the grid, thus shielding a detector behind the Anti-Scatter-Grid from undesired radiation. Besides this, the Anti-Scatter-Grid yields a signal that indicates the amount of absorbed radiation. Based on this signal it is possible to estimate the fraction of scattered radiation that is actually present and thus also the amount of scattered radiation that reaches the detector despite of the Anti-Scatter-Grid. This in turn allows to correct the image signals of the detector and to improve image quality.
  • the lamellae of the Anti-Scatter-Grid comprise a semiconductor material that converts absorbed radiation into electrical signals.
  • the electrical signals may particularly be based on the generation of free current carriers (e.g. electron-hole pairs).
  • the aforementioned semiconductor lamellae comprise a material with a low intrinsic energy conversion coefficient for the conversion of photons of the absorbed radiation into electron-hole pairs, wherein said coefficient may particularly be lower than 10 eV per electron-hole pair.
  • the lamellae comprise a scintillator material for the conversion of incident radiation of a first energy level (e.g. X-rays) into radiation of a second energy level (e.g. visible photons).
  • a first energy level e.g. X-rays
  • a second energy level e.g. visible photons
  • the second energy level of the radiation generated in the scintillator material is then typically such that it may more readily be detected, e.g. by the aforementioned semiconductor material.
  • the scintillator material is preferably disposed as an outer layer on the surface of the lamellae.
  • the lamellae may preferably comprise a material with a high absorption coefficient, particularly higher than 1 cm ⁇ 1 , for photons with energies below 150 keV.
  • a material with a high absorption coefficient particularly higher than 1 cm ⁇ 1 , for photons with energies below 150 keV.
  • the material with such a high absorption coefficient may particularly be a heavy metal with an atomic weight above 40.
  • One preferred example of a material for the lamellae is CdZnTe which has both a low intrinsic energy conversion coefficient and a high absorption coefficient for X-rays.
  • the lamellae may particularly generate an electrical signal that corresponds to the dose of absorbed radiation.
  • the lamellae are preferably covered completely or partially by electrodes, said electrodes allowing to induce an electrical field inside the lamellae and to collect charge carriers generated by absorbed radiation.
  • the electrodes may typically consist of metal, particularly of Pt.
  • one electrode may for example be located on each wall of each channel.
  • At least one of the electrodes may optionally end a distance away from the edge of the corresponding lamella on which said electrode resides. Processes in the margin of said lamella are therefore not influenced by the electrode.
  • the distance of the electrode from the edge is preferably so large that radiation will substantially (e.g. to more than 90%, preferably more than 98%) be absorbed by the material of the lamella over said distance. Therefore, (primary) radiation that is parallel to the lamellae and hits them at their edge will be absorbed in the lamella within the margin not covered by the electrode; contributions from said radiation will thus not be measured by the electrode, allowing the better separation between primary and scattered radiation. More details on this topic will be discussed in the description of preferred embodiments.
  • the aforementioned electrodes which end a distance away from the edge are preferably mixed in the Anti-Scatter-Grid with electrodes that extend to the edge.
  • the long and short electrodes may for example alternate from pixel to pixel.
  • the invention further comprises a radiation detector with the following components:
  • the signal processing unit may be adapted to discriminate fractions of incident radiation with respect to their parallelism to the channels/lamellae of the Anti-Scatter-Grid.
  • the signal processing unit may (at least approximately) determine the fraction of the incident radiation that is parallel to the channels and therefore probably primary radiation as well as the fraction of radiation that is not parallel to the channels and therefore probably scattered radiation.
  • the processing unit determines said fractions spatially resolved in order to allow a local correction of an image generated by the sensor units.
  • the invention further relates to an examination apparatus, particularly an X-ray, CT (Computed Tomography), PET (Positron Emission Tomography), SPECT (Single Photon Emission Computed Tomography) or nuclear imaging device, which comprises an X-ray sensitive radiation detector of the aforementioned kind.
  • CT Computed Tomography
  • PET Positron Emission Tomography
  • SPECT Single Photon Emission Computed Tomography
  • nuclear imaging device which comprises an X-ray sensitive radiation detector of the aforementioned kind.
  • the invention comprises a method for the determination of scattered radiation impinging on a radiation detector with an Anti-Scatter-Grid, wherein the amount of radiation absorbed by the Anti-Scatter-Grid is directly measured.
  • the measurement is preferably executed in a spatially resolved way.
  • the radiation detector, the examination apparatus and the method share the essential features of an Anti-Scatter-Grid of the kind described above. Therefore, reference is made to the preceding description for more information on the details, advantages and improvements of these objects.
  • FIG. 1 a diagrammatic side view of a part of an Anti-Scatter-Grid and an array of sensor units according to the present invention
  • FIG. 2 shows the arrangement of FIG. 1 in a perspective view together with a signal processing unit
  • FIG. 3 shows a top view of the arrangement of FIGS. 1 and 2 in which pixels with long and short anodes alternate;
  • FIG. 4 shows a top view similar to FIG. 3 according to an alternative embodiment in which all electrodes are long.
  • FIG. 1 depicts in a principal sketch (not to scale) a section through a (small part of a whole) detector array 5 of single sensor units 9 (pixels) that is disposed underneath a two-dimensional Anti-Scatter-Grid ASG.
  • Such an arrangement may for example be used in a CT device for the spatially resolved measurement of X-radiation.
  • the X-ray signal of the sensor units 9 is then a superposition of both the transmitted primary radiation 7 (the signal one is interested in) and a signal arising from scatter radiation 8 (which is undesirable and reduced by the Anti Scatter Grid ASG).
  • the presence of scattered X-rays 8 in the projections of a CT acquisition leads to cupping and shadowing artifacts, and thus visible degradation of the reconstructed CT image.
  • the scatter radiation 8 is typically of a similar order of magnitude as the primary radiation 7 , and might even cover the primary signal in areas of weak intensity. Typically, 5% to 15% of the incident scatter radiation 8 are transmitted through an ASG used in front of the detector 5 . However, especially for areas with high attenuation, the knowledge of the primary intensity is crucial for image reconstruction.
  • scatter radiation 8 is detected—if at all—by extra detector cells outside the active detector area of a CT system.
  • the scatter signal within the detector area is determined by interpolation from the values measured at the border.
  • the quality of the interpolation is—more or less—sufficient for small fan beam width, however, it does not take into account shadowing of scatter radiation by small objects within the fan beam. For large area detectors, this concept fails, since the distance between the border detectors will not give detailed information about the scatter distribution in the centre detector area.
  • the main problem outlined in the previous section is the unknown detailed distribution of scattered photons 8 in the measured tomographic projections leading to image degradation. This effect becomes even more important in future systems, since the trend towards large scan areas (cone beam) increases the amount of scatter radiation rapidly due to a larger irradiated area.
  • an approach is described that gives access to a direct measurement of the scatter distribution for the whole detector area with a spatial resolution within the range of the pixel size.
  • the basic idea of this approach is the detection/measurement of scattered X-rays 8 by the ASG itself. The measurement gives information on the spatial scatter photon distribution, allows for an improved scatter correction in the measured projections, and thus results in a higher CT image quality.
  • the Anti-Scatter-Grid ASG comprises walls or lamellae 2 of a direct conversion material that detects scattered photons 8 (“active detection”) and simultaneously absorbs these quanta analogous to a conventional ASG (“passive collimation”)—which means that the ASG acts as an “active collimator”.
  • the direct converting material may for example be a (crystalline, polycrystalline or amorphous) semiconductor which converts the energy of absorbed radiation 1 , 8 directly into electron-hole pairs.
  • the material has both a low intrinsic energy conversion coefficient (e.g.
  • the direct conversion material should have a high atomic weight Z to absorb X-ray photons most effectively (e.g. for CdZnTe: Z ⁇ 49).
  • the grid ASG is similar to a conventional two-dimensional Anti-Scatter-Grid with a typical thickness of the lamellae 2 of approximately 100 ⁇ m.
  • the height is chosen appropriately concerning absorption efficiency, technical availability, and costs with a typical range being 10 mm to 50 mm.
  • a channel is formed through which radiation 7 , 8 may pass to sensor units 9 or pixels located underneath the ASG in a detector array 5 .
  • the lamellae 2 are covered on each side by an electrode 3 , 4 , 6 , wherein the opposing electrodes are driven as anode and cathode, respectively, by an external circuit (only schematically shown in FIG. 2 for two electrodes).
  • the electrodes 3 , 4 , 6 at the sidewalls consist of a very thin layer of metal (e.g. Pt) each.
  • the metal layer must be thin enough to ensure that only a negligible amount of scattered X-rays 8 is absorbed without giving rise to a signal.
  • an electron photocurrent through the direct conversion material of the lamellae 2 is the preferred mode of operation, since the mobility-lifetime product for electrons is much higher than for holes (e.g. CdZnTe (optimized material): ⁇ e ⁇ e ⁇ 3 ⁇ 10 ⁇ 3 cm 2 /V>> ⁇ h ⁇ h 5 ⁇ 10 ⁇ 5 cm 2 /V).
  • the applied electric fields are of the order of 1 kV/cm. So, for a 100 ⁇ m thick lamella a bias voltage of only 10 V is needed to ensure sufficient charge collection efficiency. This low bias voltage involved in the operation of the detector lamellae 2 is easy to handle and makes no special protection of circuits necessary.
  • the electrode 4 (preferably the anode contact) covers the complete height of the ASG up to the upper edge of the lamella 2 .
  • electrodes 6 (anode contacts) ending a distance d short below the top edge of the lamella 2 are insensitive to radiation impinging on top of the ASG.
  • these electrodes 6 measure the whole scatter radiation 8 distribution with the exception of the distribution from the direction of the primary X-ray beam 1 , i.e. they are highly sensitive to scatter radiation 8 .
  • the short anode 6 should be at least 6 mm shorter than the long electrodes 3 , 4 .
  • Any detector pixel n of the detector gives a signal I n which is a linear combination of incident primary dose P n (radiation 1 + 7 in FIG. 1 ) and incident scatter dose S n (radiation 8 in FIG. 1 ).
  • P n incident primary dose
  • S n incident scatter dose
  • I n ⁇ n ⁇ P n + ⁇ n ⁇ S n ( ⁇ 90°).
  • the signals sampled from the scatter detector arrays have to be calibrated and corrected.
  • the coefficients an ⁇ n , ⁇ n , ⁇ n , ⁇ ′ n , ⁇ ′ n , ⁇ ′ n , and ⁇ ′′ n can be determined by an appropriate calibration procedure.
  • the scintillator pixels 9 below the ASG cognizant for detection of primary radiation 7 , will ideally have coefficients ⁇ n ⁇ 1 and ⁇ n ⁇ 0 (cf. Eq. (1)).
  • the scatter detector values I′ n including radiation impinging on top of the ASG (cf. Eq.
  • the signal intensities I n , I′ n and I′′ n are measured and the other parameters are known by a dedicated calibration procedure.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Optics & Photonics (AREA)
  • Measurement Of Radiation (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
US11/573,358 2004-08-12 2005-08-08 Anti-scatter-grid for a radiation detector Expired - Fee Related US7734017B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP04103887.8 2004-08-12
EP04103887 2004-08-12
EP04103887 2004-08-12
PCT/IB2005/052624 WO2006018779A2 (en) 2004-08-12 2005-08-08 Anti-scatter-grid for a radiation detector

Publications (2)

Publication Number Publication Date
US20090225938A1 US20090225938A1 (en) 2009-09-10
US7734017B2 true US7734017B2 (en) 2010-06-08

Family

ID=35589520

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/573,358 Expired - Fee Related US7734017B2 (en) 2004-08-12 2005-08-08 Anti-scatter-grid for a radiation detector

Country Status (5)

Country Link
US (1) US7734017B2 (zh)
EP (1) EP1779138A2 (zh)
JP (1) JP2008510132A (zh)
CN (1) CN101002109B (zh)
WO (1) WO2006018779A2 (zh)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9076563B2 (en) 2013-06-03 2015-07-07 Zhengrong Ying Anti-scatter collimators for detector systems of multi-slice X-ray computed tomography systems
US9782138B2 (en) 2014-10-01 2017-10-10 Koninklijke Philips N.V. Imaging apparatus and method
US9993219B2 (en) * 2015-03-18 2018-06-12 The Board Of Trustees Of The Leland Stanford Junior University X-ray anti-scatter grid with varying grid ratio
US20210290195A1 (en) * 2020-03-20 2021-09-23 Canon Medical Systems Corporation Photon counting detector based edge reference detector design and calibration method for small pixelated photon counting ct

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007027921B4 (de) 2007-06-18 2009-04-16 Siemens Ag Sensoranordnung, bildgebende radiologische Anlage und bildgebendes Verfahren
DE102007047844B4 (de) * 2007-11-22 2015-08-13 Koenig & Bauer Aktiengesellschaft Bahnleiteinrichtung einer Druckmaschine sowie Strangführung im Überbau
US8873703B2 (en) * 2008-05-08 2014-10-28 Arineta Ltd. X ray imaging system with scatter radiation correction and method of using same
EP2291680B1 (en) * 2008-06-16 2015-05-06 Koninklijke Philips N.V. Radiation detector and a method of manufacturing a radiation detector
WO2010015959A2 (en) 2008-08-07 2010-02-11 Koninklijke Philips Electronics N.V. Combined asg, cathode, and carrier for a photon detector
DE102014207324A1 (de) * 2014-04-16 2015-10-22 Siemens Aktiengesellschaft Direktkonvertierender Röntgenstrahlungsdetektor und CT-System
WO2017070961A1 (en) 2015-10-30 2017-05-04 Shanghai United Imaging Healthcare Co., Ltd. Anti-scatter grid for radiation detector
DE102016205702B4 (de) * 2016-04-06 2017-12-14 Siemens Healthcare Gmbh Röntgendetektor mit Schutzelement und Klebeelement
WO2018095983A1 (en) * 2016-11-24 2018-05-31 Koninklijke Philips N.V. Anti-scatter grid assembly for detector arrangement
US11350892B2 (en) * 2016-12-16 2022-06-07 General Electric Company Collimator structure for an imaging system
CN107242879B (zh) * 2017-05-17 2023-09-15 上海六晶科技股份有限公司 一种防散射格栅
EP3444826A1 (en) 2017-08-14 2019-02-20 Koninklijke Philips N.V. Low profile anti scatter and anti charge sharing grid for photon counting computed tomography
EP3675741A4 (en) 2017-08-31 2020-09-09 Shanghai United Imaging Healthcare Co., Ltd. FOCAL CT POINT DETERMINATION METHOD AND SYSTEM
WO2019144324A1 (en) * 2018-01-24 2019-08-01 Shenzhen Xpectvision Technology Co., Ltd. Packaging of radiation detectors in an image sensor
WO2019144342A1 (en) * 2018-01-25 2019-08-01 Shenzhen Xpectvision Technology Co., Ltd. Packaging of radiation detectors
CN108577880B (zh) * 2018-05-18 2022-05-27 上海联影医疗科技股份有限公司 防散射栅格及ct探测系统
DE102019210204A1 (de) * 2019-07-10 2021-01-14 Carl Zeiss Industrielle Messtechnik Gmbh Verfahren zum Korrigieren von Streustrahlung in einem Computertomographen und Computertomograph
WO2023087123A1 (en) * 2021-11-16 2023-05-25 Shenzhen Xpectvision Technology Co., Ltd. Image sensors with shielded electronics layers

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5750674A (en) 1980-09-11 1982-03-25 Toshiba Corp Radiation detector
JPH01313789A (ja) 1988-06-13 1989-12-19 Toshiba Corp 放射線検出器
JP2000070254A (ja) 1998-08-27 2000-03-07 Hitachi Medical Corp Ｘ線検出器
US6618466B1 (en) 2002-02-21 2003-09-09 University Of Rochester Apparatus and method for x-ray scatter reduction and correction for fan beam CT and cone beam volume CT

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5750674A (en) 1980-09-11 1982-03-25 Toshiba Corp Radiation detector
JPH01313789A (ja) 1988-06-13 1989-12-19 Toshiba Corp 放射線検出器
JP2000070254A (ja) 1998-08-27 2000-03-07 Hitachi Medical Corp Ｘ線検出器
US6618466B1 (en) 2002-02-21 2003-09-09 University Of Rochester Apparatus and method for x-ray scatter reduction and correction for fan beam CT and cone beam volume CT

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9076563B2 (en) 2013-06-03 2015-07-07 Zhengrong Ying Anti-scatter collimators for detector systems of multi-slice X-ray computed tomography systems
US9782138B2 (en) 2014-10-01 2017-10-10 Koninklijke Philips N.V. Imaging apparatus and method
US9993219B2 (en) * 2015-03-18 2018-06-12 The Board Of Trustees Of The Leland Stanford Junior University X-ray anti-scatter grid with varying grid ratio
US20210290195A1 (en) * 2020-03-20 2021-09-23 Canon Medical Systems Corporation Photon counting detector based edge reference detector design and calibration method for small pixelated photon counting ct
US11779296B2 (en) * 2020-03-20 2023-10-10 Canon Medical Systems Corporation Photon counting detector based edge reference detector design and calibration method for small pixelated photon counting CT apparatus

Also Published As

Publication number Publication date
CN101002109B (zh) 2011-02-09
CN101002109A (zh) 2007-07-18
WO2006018779A2 (en) 2006-02-23
EP1779138A2 (en) 2007-05-02
US20090225938A1 (en) 2009-09-10
JP2008510132A (ja) 2008-04-03
WO2006018779A3 (en) 2006-06-15

Similar Documents

Publication Publication Date Title
US7734017B2 (en) Anti-scatter-grid for a radiation detector
Hunt et al. Evaluation of the imaging properties of an amorphous selenium‐based flat panel detector for digital fluoroscopy
US7403589B1 (en) Photon counting CT detector using solid-state photomultiplier and scintillator
US7671342B2 (en) Multi-layer detector and method for imaging
US7486764B2 (en) Method and apparatus to reduce charge sharing in pixellated energy discriminating detectors
US8063380B2 (en) Semiconductor crystal high resolution imager
US9116248B2 (en) Detector array having effective size larger than actual size
EP3623848B1 (en) Scatter estimation and/or correction in x-ray imaging
KR20200024299A (ko) x-선 영상화 시스템에서 기하학적 오정렬 관리
JP2008311651A (ja) 半導体光電子増倍器の構造
EP0990254A1 (en) Multimedia detectors for medical imaging
Verger et al. Performance and perspectives of a CdZnTe-based gamma camera for medical imaging
US8552386B2 (en) Image acquisition devices with contrast and spatial resolution enhanced back-scatter shielding
RU2567436C2 (ru) Детектор излучения с направляющими электродами
JP2007271406A (ja) エネルギー較正方法，エネルギー関心領域の設定方法、放射線検出装置及び核医学診断装置
Hunt et al. Imaging performance of an amorphous selenium flat-panel detector for digital fluoroscopy
CN110108735B (zh) 一种带有光栅结构的相干散射型x射线探测器及探测方法
Menard et al. POCI: a compact high resolution/spl gamma/camera for intra-operative surgical use
Després et al. Evaluation of a full-scale gas microstrip detector for low-dose X-ray imaging
Furukawa et al. Imaging and spectral performance of a 60μm pitch cdte double-sided strip detector
JP2007071602A (ja) 放射線検出器
Coburn et al. Results of charge sharing tests in a Ge-strip detector
Zhao et al. Characterization of a direct full-field flat-panel digital mammography detector
CN108324298B (zh) 具有像素化第二电极和散射辐射栅格的布置的x射线检测器
Zeller et al. Charge sharing between pixels in the spectral Medipix2 x-ray detector

Legal Events

Date Code Title Description
AS Assignment

Owner name: KONINKLIJKE PHILIPS ELECTRONICS N.V., NETHERLANDS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ZEITLER, GUNTER;VOGTMEIER, GEREON;ENGEL, KLAUS JURGEN;REEL/FRAME:018862/0081

Effective date: 20050809

Owner name: KONINKLIJKE PHILIPS ELECTRONICS N.V.,NETHERLANDS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ZEITLER, GUNTER;VOGTMEIER, GEREON;ENGEL, KLAUS JURGEN;REEL/FRAME:018862/0081

Effective date: 20050809

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20140608